Posts Tagged ‘antibiotics’

PARIS (AFP) — Scientists said on Sunday they had exposed key workings of a deadly superbug that has become one of the biggest nightmares for hospitals today, opening up paths for new drugs or vaccines to roll back the peril.

Clostridium difficile ranks alongside Methicillin-resistant Staphylococcus aureus (MRSA) as a hospital threat, inflicting a rising toll each year as it spreads insidiously through health facilities.

Known as “C-diff,” the bug comprises a bacterium that comes in a spore, or a hardy shell-like jacket. It naturally colonises the gut, but is not a problem for people who are healthy as it is kept in check by other intestinal bacteria.

But when antibiotics are used to treat someone who is sick, the drugs can wipe out the “good” bacteria, which leaves C. difficile to multiply uncontrolled.

As the germ reproduces, it releases toxins that cause severe diarrhoea, sometimes fatally, and colitis that can need surgical removal of the colon.

In a study published in the journal Nature, microbiologists in the United States reported that they had identified which of the two toxins released by C-diff does the big damage.

“For 20 years, we have been focusing on Toxin A. But it turns out the real culprit is Toxin B,” said researcher Dale Gerding of Loyola University in Chicago.

“This is a major finding in how C-diff causes disease in humans,” he said in a press release released by the university.

“It completely flips our whole concept of what the important toxin is with the disease.”

The team devised separate strains of the two toxins and tested them on hamsters.

Separately, scientists at Imperial College London have used X-ray crystallography to produce the first high-resolution images of the germ’s protective jacket.

The work, published in the latest issue of the journal Molecular Microbiology, is important because it opens up a theoretical path for drugs that crack open the shield, disabling the bacterium inside.

C-diff is resistant to many types of antibiotics and can bounce back in a patient who has fallen sick with the germ. In addition, the jacket makes it easily transportable on surfaces and hands.

It causes about half a million cases of sickness, and between 15,000 and 20,000 deaths, in the United States each year, the Loyola University press release said.

Jan. 20, 2009 — There has been an “alarming rise” in antibiotic-resistant head and neck infections in young children in recent years, researchers from Emory University in Atlanta report.

Specifically, researchers say more and more elementary school-aged children are developing Staphylococcus aureus (”staph,” or S. aureus) infections that do not respond to the antibiotic methicillin. The bacteria responsible for such infections are called MRSA (for methicillin-resistant Staphylococcus aureus). MRSA is a common culprit in head and neck infections, and doctors believe it’s responsible for almost every skin infection.

Before the 1980s, most MRSA infections occurred in patients who were hospitalized. But in the past decade, the bacteria have become more common in crowded community environments, such as nursing homes and prisons, and among those with no known risk factors, according to information in the journal article.

“In recent years, there have been increasing reports of community-acquired MRSA infections in children,” the authors write in the journal report.

For the study, Iman Naseri, MD, and colleagues from Emory’s department of otolaryngology reviewed pediatric head and neck infection records from more than 300 hospitals in the U.S. between 2001 and 2006.

Over the six-year period, MRSA head and neck infections in children jumped from 12% of all S. aureus infections in the study in 2001 to 28% in 2006. The average age of the children was about 6 1/2. Most MRSA head and neck infections occurred in the ears (34%), followed by the nose and sinuses (28.3%) and the throat and neck (14.2%).

The findings, published in the January issue of Archives of Otolaryngology — Head & Neck Surgery, have prompted a call for more cautious use of antibiotics. According to the FDA, increasing use of antibiotics plays a large role in the development of antibiotic resistance. The U.S. government calls antibiotic resistance a major public health threat.

“Judicious use of antibiotic agents and increased effectiveness in diagnosis and treatment are warranted to reduce further antimicrobial drug resistance in pediatric head and neck infections,” Naseri’s team writes.

The authors say their results “depict an alarming increase in MRSA in the United States.” They encourage more rapid testing of suspected head and neck infections so that caregivers may prescribe the appropriate antibiotic treatment immediately. Using the wrong antibiotics or using antibiotics to treat a viral infection (such as a cold) can lead to further drug resistance, according to the FDA.